Eli Lilly's erectile dysfunction drug Cialis can correct abnormal blood flow in patients with a certain type of muscular dystrophy and could in future be used to slow progression of the disorder, researchers said on Wednesday. The findings suggest that while Cialis can't cure the condition, known as Becker muscular dystrophy, it could be used as a treatment to slow or prevent muscle weakening and help patients retain more function for longer. Becker muscular dystrophy (BMD) is an inherited disorder that involves slowly worsening muscle weakness of the legs and pelvis. It is mostly found in boys and occurs in about 3 to 6 out of every 100,000 births. Patients with BMD often have difficulties with walking that get worse over time. There is no cure for the condition, and by the age of 25 to 30 many patients are unable to walk. In a small study involving men with the disorder, researchers from the Cedars-Sinai Medical Center, Los Angeles, in the United States took measurements when volunteers' forearm muscles were either rested or lightly exercised with a handgrip. They found that almost all the patients had defective blood flow when they exercised. This lack of blood flow may contribute to muscle fatigue and weakness, the researchers wrote in a study in the journal Science Translational Medicine.